Honda GX270H Manual page 159

62Z7B000.book 16 ページ ２０１２年９月２７日 木曜日 午前１０時２１分
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CRANKCASE
PISTON PIN O.D.
Measure and record the piston pin O.D. at three points
(both ends and middle). Take the minimum reading to
determine piston pin O.D.
GX270H:
STANDARD:
SERVICE LIMIT:
GX390H1:
STANDARD:
SERVICE LIMIT:
If the measurement is less than the service limit,
replace the piston pin.
Inspect the piston pin bore I.D. (page 14-15).
Inspect the connecting rod small end I. D. (page 14-18)
with this inspection.
PISTON PIN-TO-PISTON PIN BORE
CLEARANCE
Subtract the piston pin O.D. from the piston pin bore
I.D. to obtain the piston pin-to-piston pin bore
clearance.
STANDARD:
0.002 – 0.014 mm (0.0001 – 0.0006 in)
SERVICE LIMIT: 0.08 mm (0.003 in)
If the calculated clearance is more than the service limit,
replace the piston pin (page 14-13) and recheck the
clearance.
If the clearance is still more than the service limit with
the new piston pin, replace the piston (page 14-13).
PISTON RING SIDE CLEARANCE
Measure the clearance between each piston ring and
ring groove of the piston using a feeler gauge.
STANDARD:
Top:
Second:
SERVICE LIMIT:
Top/second:
If any of the measurements is more than the service
limit, inspect the piston ring width.
If the piston ring width is normal, replace the piston
(page 14-13) and reinspect the clearance.
If necessary, replace the piston rings (top, second, oil)
as a set (page 14-13) and reinspect the clearance.
If any of the measurements is still more than the service
limit with the new piston rings, replace the piston (page
14-13).
14-16
17.994 – 18.000 mm
(0.7084 – 0.7087 in)
17.950 mm (0.7067 in)
19.994 – 20.000 mm
(0.7872 – 0.7874 in)
19.950 mm (0.7854 in)
0.015 – 0.050 mm
(0.0006 – 0.0020 in)
0.030 – 0.065 mm
(0.0012 – 0.0026 in)
0.15 mm (0.006 in)